The Canon RF 24-105mm F4 L IS USM is a fine starter zoom for the EOS R system, even if it is a bit pricey.

Despite positioning its first full-frame mirrorless camera, the EOS R, closer to the entry side of the market than the pro one, Canon took the opposite tack with its initial batch of lenses. The RF 24-105mm f/4L IS USM ($1,099) is an excellent zoom, and one that's priced in line with its performance and similar lenses for other systems. If you're jumping in feet first and would like a native, rather than an adapted, zoom for your EOS R, the 24-105mm is the obvious choice, and will serve you well, although you will want to take advantage of software corrections when shooting in Raw format.

More Than a Kit Zoom

The term "kit zoom" is almost a dirty word in photographic circles, despite manufacturers largely offering much better starter options for SLRs and mirrorless systems in recent years than they used to. The RF 24-105mm f/4L IS USM is built, and priced, beyond even modern kit lens quality. It offers more zoom range than the Nikon Z 24-70mm f/4 S (priced around $600 when bought with a camera) and is in a different class compared with Sony's FE 28-70mm f/3.5-5.6 OSS, which goes for about $400 on its own or $200 when bundled along with a camera.

By default, the 24-105mm f/4L IS USM is the kit zoom for the EOS R. There's only one other native zoom available, the $3,000 RF 28-70mm F2 L, which is most certainly more of a niche lens than a crowd-pleaser. At press time, Canon doesn't offer any sort of discount when buying it along with a camera body, which makes entry into the EOS R system a pricier proposition than either of its mirrorless rivals. This is sure to change in time, as Canon releases more lenses at more diverse price points.

The 24-105mm bears Canon's L designation, which it reserves for its top tier. It lives up to the moniker. The barrel is polycarbonate, and internal seals prevent dust and splashes of water from intruding. It's about the same size as similar lenses for other systems, coming in at 4.2 by 3.3 inches (HD) and 1.5 pounds. The barrel does telescope when zooming, roughly doubling its length at the 105mm position when compared with 24mm. The front element supports 77mm filters and a reversible lens hood is included, as are front and rear caps.

There's one quirk with the rear caps, and it's not only an issue with the 24-105mm—it also shows up with other RF lenses. Typically putting a rear cap on a lens only takes a simple twist, but with the RF lenses you need to take care to properly line up the rear cap and the lens. There's a small notch on the cap, at the 12 o'clock position, that must be lined up with a red dash on the mount. Photographers are used to lining up a lens properly before mounting it to a camera, but will now have to learn to do the same when putting the rear cap on a lens.

In addition to the normal array of anti-reflective materials, the front and rear element are also coated with fluorine. The compound repels grease and moisture, so you can more easily wipe away water droplets and fingerprints from the exposed glass. It's becoming more and more common, and while it's not something I expect to see in every lens, I'm happy to see it included here.

There are three control rings. You get the normal zoom and manual focus controls, as well as a programmable control ring. The control ring has detents, so you can easily dial in small adjustments, and while the focus ring is electronic, it has a linear response—focus adjustments are based on how far you turn it, not how quickly. It's an important feature for video users, as it allows you to set start and end points for focus racks.

The zoom ring has set marks at the 24, 35, 50, 70, 85, and 105mm positions. There is a locking switch; it keeps the lens set at its shortest, 24mm position, so the barrel won't creep out and extend if you are carrying the camera at your side or around your neck. There are also switches to change focus modes (AF/MF), and to toggle the optical image stabilization system.

Canon has opted for lens-based stabilization for the EOS R. The 24-105mm is a stabilized lens, with five-stop correction based on CIPA's standard testing methods. I was able to get consistently blur-free shots at 1/8-second at 105mm, which is closer to four stops. At 1/4-second my results were mixed, but the lens was able to steady about half of my test images. Moving to 1/3-second was a bridge too far, as results were consistently blurred, even with the benefit of stabilization.

The lens isn't billed as a macro, but has a very good close focus capability. It can hone in on subjects as close as 17.7 inches (0.45-meter), which is good enough for 1:4.2 life-size reproduction at the closest focus distance and maximum zoom. Typically we want to see a zoom lens offer at least 1:3 magnification power in order to call it a macro.

Benefits From Corrections

I tested the RF 24-105mm with the 30.3MP EOS R and Imatest software. It's a sharp lens, even at f/4 and at the edges of the frame. It puts up 2,788 lines in a center-weighted sharpness test at 24mm f/4, and while the center of the frame is a little sharper than average, the majority of the frame, right up to the edges, nets strong results. We want to see an image that shows around 2,000 lines at a minimum when working with a 30MP sensor.

Resolution ticks up to 2,900 lines at f/5.6 and f/8, but starts to drop at f/11 (2,756 lines). The trend continues at f/16 (2,612 lines) and the minimum f/22 aperture (2,187 lines). This is expected—light passing through the very narrow opening used at the smallest f-stops diffracts (or scatters, in layman's terms), which softens detail.

At 50mm the lens is not quite as sharp at f/4 (2,565 lines), but still shows strong performance from center to edge. It ticks up at f/5.6 (3,037 lines) and f/8 (3,061 lines). We see the expected small drop at f/11 (2,923 lines), and larger ones at f/16 (2,717 lines) and f/22 (2,302 lines). Performance is very similar at 75mm—2,823 lines at f/4, 3,013 at f/5.6, 3,200 at f/8, 3,036 at f/11, 2,809 at f/16, and 2,399 at f/22.

Some 24-105mm lenses lose a bit of resolution at the longest focal length. It's not the case with this one. At 105mm f/4 we still see 2,693 lines, and resolution increases as expected at f/5.6 (3,071 lines) and f/8 (3,070 lines). We see the same drops at narrower settings—2,730 lines at f/11, 2,566 lines at f/16, and 2,202 lines at f/22.

In summary, the 24-105mm is solidly in the very good class at f/4, and improves to excellent from f/5.6 through around f/11. If resolution was all that mattered, I'd have very little to complain about with the lens.

We also look at distortion and uniformity of illumination. The lens does show a bit of barrel distortion at 24mm, 2.7 percent. It's enough to give photos with straight lines—think the horizon or architectural details—a very mild fish-eye bulge. It gives way to pincushion distortion as you zoom, which has the opposite effect. The lens shows about 1.5 percent at 50 and 75mm, and 1.7 percent at 105mm. The EOS R can remove distortion automatically if you shoot in JPG format, and there's really no reason not to enable the correction if you don't want to deal with making manual software corrections to remove it. If you shoot in Raw format the distortion is easily removed, either with a manual adjustment or an Adobe lens profile.

The lens also shows a vignette. As with distortion, the EOS R automatically applies some level of vignette correction when shooting in JPG—you can turn the feature off, but I wouldn't. Even with the correction there is darkening at the corners (-2.3EV) and sides (-1.4EV) at 24mm f/4. It's enough to notice visually in many images, but it's not nearly as strong as the uncorrected image, which shows a -5.6EV drop at the corners and -2.7EV at the sides of the frame. Raw photographers will likely want to brighten them, at least partially. The same Lightroom profile that removes distortion also corrects for the vignette.

The vignette lessens as you narrow the aperture at 24mm, but never really goes away. It does lessen by the time you've zoomed to 50mm—the automatic corrections all but eliminate it at f/4, and the uncorrected image shows a noticeable -2.3EV drop—easily fixed in Lightroom. At narrower apertures the vignette isn't noticeable, even without correction. Results are very similar at 75mm.

We see a little bit of darkening at the corners in corrected 105mm f/4 images, but just about -1.2EV. The uncorrected shot shows -3.7EV, which is more noticeable, although it may add a bit of a natural frame for portraits. It drops to -2EV at f/5.6 and is negligible at smaller f-stops.

I wouldn't fret at all about distortion—correcting it can slightly narrow your angle of view, but it's not worth complaining about. If you're working at a lower ISO, the vignette corrections won't introduce too much additional noise to photos, but do remember that pushing the exposure at the corners can add some grain at a higher ISO.

The Beginning of a Promising Lens System

The Canon RF 24-105mm F4 L IS USM is likely to be the first lens many EOS R owners purchase. For first-time Canon buyers intrigued by the new mirrorless system, it's a solid introduction—a well-made zoom with a very useful range, strong close-up capability, and sharp optics. It's not perfectly corrected for distortion, and doesn't have the head-turning f/2 design of the RF 28-70mm, but not everyone wants a three-pound, $3,000 lens as their everyday zoom.

If you're already a Canon SLR owner and are intrigued by the EOS R, you may also find yourself considering splurging for a native lens instead of using your existing glass via an . If you already have a good zoom that covers the range, it's a tough pill to swallow.

Part of that is because Canon doesn't offer a discount when buying it with a camera. It's not alone—Sony also bundles its FE 24-105mm without a discount, and it's a little bit more expensive to boot. But Sony has other starter zooms that are available in discounted bundles, while Canon doesn't. This is certain to change over time, and if you're reading this a few years into the life of the RF system—lenses stay in the market for a long, long time—the situation is certain to have changed.

The growing pains of a just-born camera system are something early adopters must endure. I don't think Canon did itself a favor by omitting a budget option from its first batch of RF lenses, but that doesn't take away from the quality you get from the RF 24-105mm F4 L IS USM. It's an excellent lens, priced in line with other first-party options, and will no doubt remain a staple choice, even as Canon grows the RF system.

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About the Author

Senior digital camera analyst for the PCMag consumer electronics reviews team, Jim Fisher is a graduate of the Rensselaer Polytechnic Institute, where he concentrated on documentary video production. Jim's interest in photography really took off when he borrowed his father's Hasselblad 500C and light meter in 2007. He honed his writing skills at re... See Full Bio

Canon RF 24-105mm F4 L IS USM

Canon RF 24-105mm F4 L IS USM

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